Password Criterion - D-Link DFL-1600 User Manual

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The secret information that only the involved user knows and keeps,
such as the most commonly used Password or a Shared secret phrase.
The difficulty of using method a) is that it requires some special devices to
scan and read the feature presented, which are relatively expensive.
Another risk that may cause this to fail is that the features are almost
impossible to have substitutes; in case the user loses the feature by
accident, nothing can be used for replacement.
Therefore, the more commonly used methods for network services are (b)
and (c). There are also potential risks by using either of these methods, for
example, the keys may be intercepted, the card can be stolen, people tend
to use weak passwords that are easy to guess, and they may be bad on
keeping any secret, and so on. Thus, these two approaches are often
combined to have add one factors and security levels. For example, a
passcard is often granted to a person with a password.
User authentication is frequently used in services, such as HTTP, FTP, and
VPN. D-Link firewalls use Username/Password as primary authentication
method, strengthened by encryption algorithms. The basic concepts of
encryption is covered by
and secure means of authentication, such as the Public-private Key System,
X.509 Certificate, IPsec& IKE, IKE XAuth, and ID List are introduced in:
20.2.2 Authentication &
17.1.2

Password Criterion

In the Username/Password coupling, the username(account name) as an
identifier tells who you are, and the password severs as an authenticator to
prove that this is true. To penetrate certain system and obtain the user or
administrator's privileges, the password is often subject to attacks.
Attacks
There are mainly three different ways to attack a password:
Guess:
Try possible cases. Passwords that are chosen from a dictionary, or
user's personal information, such as name, telephone number, and
birth date are vulnerable to this attack.
Find:
20.2 Introduction to
Integrity, and 22 VPN Protocols &
D-Link Firewalls User's Guide
Chapter 17. User Authentication
Cryptography. More advanced
Tunnels.